The present disclosure relates to a secondary cell, a method for manufacturing a secondary cell, a positive electrode for secondary cells, a method for manufacturing a positive electrode for secondary cells, a battery pack, an electronic device, and an electric vehicle. More specifically, the present disclosure relates to a secondary cell that has a sulfur-containing positive electrode and such a positive electrode, methods for manufacturing such a secondary cell and such a positive electrode, and the application of such a secondary cell.
Lithium-sulfur cells, which are secondary cells in which the active material for the positive electrode is sulfur, are of public interest because this type of secondary cell can have much better recharge performance than lithium-ion cells (e.g., see Japanese Unexamined Patent Application Publication Nos. 2005-251473, 2009-76260, and 2003-197196). A lithium-sulfur cell usually has a positive electrode made of crystalline sulfur (or cyclosulfur) (S8), a negative electrode made of metallic lithium, and a non-aqueous electrolyte that contains lithium ions (Li+). Sulfur alone is of very low conductivity and is usually mixed with a conducting agent so that an effective active material can be obtained. Sulfur can be in a particulate form when mixed with a conducting agent so that continuity can be more easily provided and better characteristics can be obtained.